Once on scene, two revellers on a bridge overhead pointed out the casualty to RNLI crews as they raced to save his life.

The pair were believed to have been on their way home from a night out and saved precious time in locating the man.

RNLI crewman Matt Leat said: “The lads were pointing towards two large boats moored in the middle of the river so we zoomed over. It was dark and he was well hidden from view, but we could just make out a face poking out above the water between the two boats.

“The tide was flowing fast, funneling water between the vessels, which made it very difficult to get to the casualty. Our helmsman skillfully maneuvered the lifeboat into position which allowed the crew to reach the man and pull him aboard to safety.”

After retrieving the casualty from the water, rescue crews took him to Tower lifeboat station next to Waterloo Bridge where he was handed into the care of the London Ambulance Service.

The man did not suffer any lasting injuries and the rescue has been classed as a life saved, meaning the person would have most likely died if not for one of the charity’s lifeboat crews rescuing them.

“Once he was in the river he only had minutes to live. The River Thames is very cold and you can only cling onto something for so long before hypothermia sets in and you lose your ability to grip.

“If this man had let go of the mooring lines, he most likely would have been lost to the strong currents flowing between the vessels and died,” added Mr Leat.